# US 2021/0342016 A1 · Wheel assembly and associated input device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0342016 A1 - Document ID: US20210342016A1 - Status: Published application - Kind: A1 - Application number: 16/462,869 - Filed: 2016-11-30 - Published: 2021-11-04 - Earliest claimed: 2016-11-30 - Assignees: Microsoft Technology Licensing, LLC - Applicants: Microsoft Technology Licensing, LLC - Inventors: Wensheng YAO; Chunlai ZHANG; Ke ZHAO - Web page: https://patentgrep.com/patent/US20210342016A1 ## CPC - G06F 3/0362: with detection of one-dimensional [1D] translations or rotations of an operating part of the device, e.g. scroll wheels, sliders, knobs, rollers or belts - G01D 5/145: {influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06)} - G06F 3/03541: {Mouse/trackball convertible devices, in which the same ball is used to track the 2D relative movement} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR ## Abstract Embodiments of present disclosure relates to a wheel assembly that can be used with mouse or other input device. The wheel assembly includes a wheel, a magnet for generating a magnetic field, and at least three magnetic sensors for sensing an absolute angular position of the wheel. The magnet coupled to the wheel and operable to rotate with a rotation of the wheel. The at least three magnetic sensors are arranged within a plane that is located in a predetermined distance from the magnet and substantially parallel to a main direction of the magnetic field generated by the magnet. Compared to the conventional sensors that measure the relative position of the wheel, such multiple magnetic sensors based wheel assembly enables a direct absolute angular position measurement. ## Claims ### Claim 1 A wheel assembly (100) for use in an input device (200), the wheel assembly (100) comprising: a wheel (3); a magnet (2) coupled to the wheel (3) for generating a magnetic field and operable to rotate with a rotation of the wheel (3); and at least three magnetic sensors (1) for sensing an absolute angular position of the wheel (3), the at least three magnetic sensors (1) being arranged within a plane (10) that is located in a predetermined distance (Y) from the magnet (2) and substantially parallel to a main direction (B) of the magnetic field generated by the magnet (2). ### Claim 2 (depends on 1) The wheel assembly (100) of claim 1, wherein the magnet (2) is a permanent magnet. ### Claim 3 (depends on 1) The wheel assembly (100) of claim 1, wherein the magnet (2) has a cylindrical shape and includes a semi-cylindrical North pole (N) and a semi-cylindrical South pole (S). ### Claim 4 (depends on 1) The wheel assembly (100) of claim 1, wherein the magnet (2) includes a plurality of North poles (N) and a plurality of South poles (S). ### Claim 5 (depends on 3) The wheel assembly (100) of claim 3, wherein the at least three magnetic sensors (1) are substantially equally spaced along a tangential direction (C) of the rotation of the wheel (3). ### Claim 6 (depends on 5) The wheel assembly (100) of claim 5, wherein the at least three magnetic sensors (1) are arranged on a circle (20). ### Claim 7 (depends on 1) The wheel assembly (100) of claim 1, wherein the at least three magnetic sensors (1) are Hall sensors. ### Claim 8 (depends on 6) The wheel assembly (100) of claim 6, wherein an area (S1) of a cross section of the magnet (2) is larger than an area (S2) of the circle (20). ### Claim 9 (depends on 8) The wheel assembly (100) of claim 8, wherein the circle (20) is coaxially aligned with the magnet (2). ### Claim 10 (depends on 8) The wheel assembly (100) of claim 8, wherein the circle (20) has a diameter in a range of 1 mm-3 mm, and the cross section of the magnet (2) has a diameter in a range of 4 mm to 6 mm. ### Claim 11 An input device (200), comprising: a wheel (3); a magnet (2) coupled to the wheel (3) for generating a magnetic field and operable to rotate with a rotation of the wheel (3); at least three magnetic sensors (1) for sensing an absolute angular position of the wheel (3), the at least three magnetic sensors (1) being arranged within a plane (10) that is located in a predetermined distance (Y) from the magnet (2) and substantially parallel to a main direction (B) of the magnetic field generated by the magnet (2); an analog-to-digital convertor (ADC) (210) for converting a magnetic field detected by the at least three magnetic sensors (1) into a measurable electrical signal; and a gain control mechanism (220) for adjusting an intensity of the electrical signal. ### Claim 12 (depends on 11) The input device (200) of claim 11, wherein the magnet (2) has a cylindrical shape and includes a semi-cylindrical North pole (N) and a semi-cylindrical South pole (S). ### Claim 13 (depends on 11) The wheel assembly (100) of claim 11, wherein the magnet (2) includes a plurality of North poles (N) and a plurality of South poles (S). ### Claim 14 (depends on 12) The input device (200) of claim 12, wherein the at least three magnetic sensors (1) are substantially equally spaced along a tangential direction (C) of the rotation of the wheel (3). ### Claim 15 (depends on 14) The input device (200) of claim 14, wherein the at least three magnetic sensors (1) are arranged on a circle (20). ### Claim 16 (depends on 11) The input device (200) of claim 11, wherein the at least three magnetic sensors (1) are Hall sensors. ### Claim 17 (depends on 15) The input device (200) of claim 15, wherein an area (S1) of a cross section of the magnet (2) is larger than an area (S2) of the circle (20). ### Claim 18 (depends on 16) The input device (200) of claim 16, wherein the circle (20) has a diameter in a range of 1 mm-3 mm, and the cross section of the magnet (2) has a diameter in a range of 4 mm to 6 mm. ### Claim 19 (depends on 11) The input device (200) of claim 11, wherein the at least three magnetic sensors (1), the ADC (210) and the gain control mechanism (220) are integrated on a same circuit board. ### Claim 20 A method of manufacturing a wheel assembly (100), comprising: providing a wheel (3); coupling a magnet (2) for generating magnetic field to the wheel (3) in such a way that the magnet (2) rotates with a rotation of the wheel (3); providing at least three magnetic sensors (1) for sensing an absolute angular position of the wheel (3); and arranging the at least three magnetic sensors (1) within a plane (10) that is located in a predetermined distance (Y) from the magnet (2) and substantially parallel to a main direction (B) of the magnetic field generated by the magnet (2).